Conductive Particle Preparation via Gamma Radiation Carbonization
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Solution Overview
Problem
The use of carbon-based materials as conductive fillers in conductive adhesives faces challenges due to difficulty in uniform dispersion and varying electrical conductivity, which affects processing and repeatability in electronic device manufacturing.
Innovation Solution
A method is developed to create conductive particles by forming spherical cores, polymerizing organic monomers on their surfaces using γ-ray radiation, followed by preoxidation and carbonization, resulting in a uniform conductive layer of carbon particles, which improves dispersibility and stability of conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon-based materials are used as conductive fillers to reduce cost, then manufacturing cost is reduced, but processing difficulty increases and electrical conductivity varies greatly
Solution Approach 1:
The patent applies preliminary action by pre-coating carbon particles with a silica shell before incorporating them into the adhesive. This pre-preparation step ensures uniform size, shape, and surface properties of the conductive fillers, which eliminates processing difficulties and conductivity variations that would otherwise occur during manufacturing. The silica coating is formed through controlled hydrolysis and condensation reactions of tetraethyl orthosilicate on the carbon particle surfaces.
Solution Approach 2:
The patent employs parameter changes by controlling the particle size, shell thickness, and carbon-to-silica ratio of the coated particles. By optimizing these parameters, the invention achieves both ease of processing (through uniform dispersion) and reliable electrical conductivity (through controlled carbon content). The particle size is controlled within a specific range, and the silica shell thickness is adjusted to balance conductivity and dispersibility.
2Quantity of substance
If carbon-based materials are used as conductive fillers, then cost is reduced, but uniform dispersion in mainbody glue material becomes difficult
Solution Approach 1:
The patent uses a silica coating layer as an intermediary between the carbon particles and the mainbody glue material. This intermediate silica shell improves the compatibility and dispersibility of carbon particles in the adhesive matrix, preventing aggregation and ensuring uniform distribution. The silica surface can interact favorably with both the carbon core and the organic binder, acting as a bridge that enhances overall dispersion stability.
Solution Approach 2:
The patent creates a composite material structure consisting of a carbon core surrounded by a silica shell. This composite design combines the electrical conductivity of carbon with the dispersibility and stability of silica. The resulting coated particles exhibit both low cost (from carbon) and uniform dispersion characteristics (from silica), resolving the contradiction between cost and compositional stability.
3Reliability
If Au or Ag particles are used as conductive fillers, then electrical conductivity and chemical stability are improved, but manufacturing cost increases sharply
Solution Approach 1:
The patent applies this principle by replacing expensive precious metal particles (Au, Ag) with inexpensive carbon-based particles that provide sufficient conductivity for the application. The carbon particles, while less conductive than precious metals, offer adequate electrical performance at a fraction of the cost, making large-scale production economically viable without sacrificing essential functionality.
Solution Approach 2:
The patent uses composite materials by combining carbon particles with a silica coating to create a filler that approaches the performance of precious metals at a fraction of the cost. The silica-cored carbon composite structure optimizes both electrical conductivity and dispersibility, providing a cost-effective alternative to Au or Ag particles while maintaining reliable electrical connections in the adhesive.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables uniform distribution and enhanced electrical conductivity of carbon particles, overcoming the challenges of dispersion and variability in traditional methods, while reducing the risk of aggregation and improving the cost-effectiveness of conductive adhesives for large-scale production.
Implementation Method 1
radiating the reaction solution with γ rays so that the organic polymeric monomers are polymerized on surfaces of the cores
Implementation Method 2
the organic polymeric monomers are polymerized on surfaces of the cores so as to form organic polymers
Implementation Method 3
successively carrying out preoxidation and carbonization treatment on the cores formed with the organic polymers on their surfaces
Implementation Method 4
carrying out preoxidation and carbonization treatment on the cores formed with the organic polymers on their surfaces so that the organic polymers form a conductive layer consisting of carbon particles
Data Source
AI summary
The present disclosure provides a conductive particle and a preparation method thereof, a conductive adhesive and a display device. The preparation method comprises steps of: forming cores; dispersing the spherical cores in deionized water and adding organic polymeric monomers so as to form a reaction solution; radiating the reaction solution with γ rays so that the organic polymeric monomers are polymerized on surfaces of the cores so as to form organic polymers; separating the spherical cores formed with the organic polymers on their surfaces from the reaction solution so as to obtain them; successively carrying out preoxidation and carbonization treatment on the cores formed with the organic polymers on their surfaces so that the organic polymers form a conductive layer consisting of carbon particles so as to obtain conductive particles each consisting of the conductive layer and the core.